The invention generally relates to room divider systems and devices used for locking adjoining panels in the system together. The invention is more directly related to wall panel systems supported by vertical frame members, particularly of the type used to divide office space into individual work spaces or stations. The invention is particularly directed to wall panel systems having panels removably supported on vertical frame members wherein the wall panel arrangement may be readily re-arranged.
Typically, office wall panel divider systems are erected with tubular vertical frame members that abut one another and which are individually connected to horizontal upper and lower frame members to form a panel frame for the mountable attachment of decorative wall panels thereon. In order to fasten the system together, the vertical frame members in the prior art have been interlocked in a variety of ways. One standard method is to provide for a hook-type engagement wherein a hook, tang, prong-like projection, or the like, on one vertical frame member engages a matable slot, notch, aperture, etc., in the other. Thereafter, mechanical fasteners are typically utilized to lock the two frame members at a location elsewhere along the length of the adjacent vertical member. Both the hook and the mechanical fastener connect the vertical frame members and thereby secure the panel frames.
The typical utilization of bolts and other threaded fasteners, including lock nuts and the like, for locking panel frames together have generally required the use of hand tools. It would be desirable to eliminate the need for hand tools and yet provide a very secure interlock between the vertical frame members.
Some systems have used a past-center type of camming device that does not require the use of hand tools for interlocking panels. One type of such device is shown in U.S. Pat. No. 4,881,349, wherein vertical frame members are provided to have aligned slot-like openings. A "T" end of a two-piece hinged clamping member is passed through the slots and then rotated 90.degree.. A second part of the clamp consists of an actuator that is pivotally connected at two points on the opposite end of the "T" end member and includes camming surfaces for camming against the exterior of the other frame member when rotated about 90.degree. to a past-center locked position. That system however creates a need for elongate abutment strips arranged along the vertical frame members, which that are compressible upon locking to help accurately align the panels and tighten otherwise loose fits together in a snug arrangement. The system of U.S. Pat. No. 4,881,349 allows for no relative adjustment of the two-piece clamping members caused by the material irregularities, deformations, slots form outside of tight-fit, tolerances and the inherent disparity in the hinged "play" in the freely pivotal actuator member. The use of the resilient abutting strip might therefore become a necessary element to take up the slack caused by errors in machining tolerances, material and dimension errors in fabrication, and other manufacturing defects, even though slight.
This camming-type of actuator device of U.S. Pat. No. 4,881,349 also does not allow for the utilization of washers, or other forced-distributing means, that would offer a more even surface for distributing the locking force on the faces of tubular frame members. Washers, or the like, cannot be used because the actuator and "T"-shaped insert members are hingedly joined together permanently during manufacturing and allow for no introduction of a force distributing element to aid in securement or provide for a sure camming surface for the actuator member. The actuator member of this prior art patent pulls the "T"-shaped insert member directly against the face of the frame members in two point loadings made by each arm of the "T", which can cause material deformation, damage, and loose connections as the actuator moves past-center.
Past-center mechanical fasteners have long been used in various applications for locking doors, luggage, containers, window locks, etc. These types of fasteners are typified in U.S. Pat. Nos. 1,451,768 and 1,229,851, wherein past-center cam locks are designed pivot a lever and draw a member toward the lever into a past--or over--center latching position. Such fasteners have not suggested utilization in a wall panel system which would allow for adjustment of the fastener members and have means for inserting and locking one member, while rotatably allowing the camming member to be adjustably positioned prior to pivoting in order to compensate for tolerance variations and thereby achieve a snug fit.
The invention as described below addresses the need in the art for a past-center interlock system which allows for adjustment and achieves a quick and sure connection of frame members requiring only one manually installed interlock per joint when used in cooperation with, for example, a standard hook and slot lock at another location along the frame members.
The invention also satisfies a goal in the panel system by permitting the insertion of an interlock from only one side of a frame joint, so that wall panels supported on an adjacent panel frame need not be removed in order to change the panel configuration of the next panel frame as might be needed during office space remodeling.